Torques exerted by Gravity (CONFUSING)

1. The problem statement, all variables and given/known data
A door with symmetry and of m 43.1 kg is 4.76 m high and 2.68 wide. The hinges are placed all the way on top and all the way on the bottom of the door. Find the absolute value of the horizontal force supplied by the bottom hinge.

2. Relevant equations
Sum of torques = 0
Torque = R x F

3. The attempt at a solution
I tried finding the torque exerted by gravity... and equaling that to the torque exerted by the hinges...
F(L)=W/2(mg)
now would i divide the force by 2 since there are 2 hinges?
or is my reasoning wrong from the first place?

Staff: Mentor

First, draw a diagram showing the forces (including gravity) acting on the object. Next, pick a point of rotation. (Of course, you always pick a point that eliminates one or more of the unknowns.) And then, you apply the torque equation.

Staff: Mentor

Doc Al... i contacted him again and i was told, "Its not just a product but a CROSS PRODUCT"...
but in a vertical door arent all the torques exerted by gravity perpendicular??
im confused

It certainly is a cross-product, not just a scalar product, but what you did was fine. To find the torque due to gravity, you took the force (mg) and multiplied it by the perpendicular component of the distance to the axis (W/2). All perfectly correct.